Colorimetric Sensing of Amoxicillin Facilitated by Molecularly Imprinted Polymers.

Joseph W Lowdon,Hanne Diliën,Thomas J Cleij,Bart Van Grinsven,Kasper Eersels

doi:10.3390/polym13132221

Abstract

The scope of the presented research orientates itself towards the development of a Molecularly Imprinted Polymer (MIP)-based dye displacement assay for the colorimetric detection of the antibiotic amoxicillin in aqueous medium. With this in mind, the initial development of an MIP capable of such a task sets focus on monolithic bulk polymerization to assess monomer/crosslinker combinations that have potential towards the binding of amoxicillin. The best performing composition (based on specificity and binding capacity) is utilized in the synthesis of MIP particles by emulsion polymerization, yielding particles that prove to be more homogenous in size and morphology compared to that of the crushed monolithic MIP, which is an essential trait when it comes to the accuracy of the resulting assay. The specificity and selectivity of the emulsion MIP proceeds to be highlighted, demonstrating a higher affinity towards amoxicillin compared to other compounds of the aminopenicillin class (ampicillin and cloxacillin). Conversion of the polymeric receptor is then undertaken, identifying a suitable dye for the displacement assay by means of binding experiments with malachite green, crystal violet, and mordant orange. Once identified, the optimal dye is then loaded onto the synthetic receptor, and the displaceability of the dye deduced by means of a dose response experiment. Alongside the sensitivity, the selectivity of the assay is scrutinized against cloxacillin and ampicillin. Yielding a dye displacement assay that can be used (semi-)quantitatively in a rapid manner.

Highlights

Since the discovery of modern-day antibiotics in the early 20th century, these miracle molecules have gone from a wonder drug to one of the world’s largest environmental contaminants [1]
The four compositions consisted of either methacrylic acid, acrylamide, and either EGDMA or TRIM as crosslinker (EGDMA producing a more flexible structure, and TRIM a more rigid network)
The binding properties of the Molecularly Imprinted Polymer (MIP) were tested by means of batch rebinding experimentation, where the MIPs were exposed to increasing concentrations (0.1–0.7 mM) of amoxicillin for a defined time (90 min)

Summary

Introduction

Since the discovery of modern-day antibiotics in the early 20th century, these miracle molecules have gone from a wonder drug to one of the world’s largest environmental contaminants [1]. It is common practice to supplement animal feed with antibiotics, ensuring the health and welfare of the creature by reducing the risk of illness or facilitating the rapid recovery from bacterial ailments [4]. Though this is beneficial for the animal in question, it generates an environmental concern. The concentrations of antibiotics in the environment is increasing, and the bacteria that are exposed consistently to these compounds become resistant to their destructive effects This is just one concern related to the over-use of antibiotics in animals, another is the transfer of antibiotics in animal-related byproducts, e.g., milk [7]. This makes the detection of antibiotics in both animal waste and in by-products essential, as both the environment and animals (humans) are at risk due to the potential of stimulating and further progressing antibiotic-resistance

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Discussion

Conclusion